Conventionally, as such kind of seat belt anchorage plate, a plate illustrated in FIG. 38 has been well known. That is, a seat belt anchorage plate comprises a base (plate shaped member) 2 having a bolt hole 3 and a slot 69 formed thereon and is designed to be secured to a fixed part such as a vehicle body through the bolt hole 3 and to be connected to a belt 13 through the slot 69.
The belt 13 employs a thin band shaped woven fabric in which for example, polyester fibers are woven and is folded back in one long edge part 691-8 of the slot 69, so that tension is exerted on the one long edge part 691-8 which is linearly formed.
Since the above mentioned conventional seat belt anchorage plate has one long edge part 691 formed in a straight line, when the tension of the belt 13 is not exerted in the direction perpendicular to the one long edge part 691-8, the belt 13 is liable to laterally slide on the one long edge part 691-8 and come together to the end part of the long edge part 691-8. In other words, there has been encountered a problem that the belt is apt to be gathered to the end part of one long edge part 691-8. Even if the tension of the belt 13 is exerted in the direction perpendicular to the one long edge part 691-8, for example, according to an examination through a strength measuring test, the belt 13 itself will be thinly converged and tend to meet at one part on the one long edge part 691-8 when the tension is exerted on the belt 13. Further, since the one long edge part 691-8 is elastically bent and slightly recessed by virtue of the tension of the belt 13, the belt 13 is undesirably liable to be gathered to one part on the long edge part 691-8 in addition to the defect that the belt 13 itself thinly converges into one part.
Further, the belt 13 is advantageously curved so as to be folded along a center line in its longitudinal direction in order to maintain the flat state of the belt 13. Therefore, the belt 13 is normally inserted into the slot 69 under its curved state as stated above. However, when the belt 13 is curved in such a way, there arises a problem that both ends at the right and left sides of the belt 13 abut against, for example, both right and left ends of the one long edge part 691-8, and therefore, the belt 13 is inserted into the slot 69 with difficulty. As shown in FIG. 38, when both the end parts of the belt 13 swell out roundly, there also arises a problem that these swelling parts tend to more easily abut against both the end parts of one long edge part 691-8.
Still further, the slot 69 is formed by a press working. In this case, burs are liable to be formed at the corner parts in the side punched out by a press. When such burs are left as they are, they have possibility to cause an action similar to that of a cutter. Accordingly, the corner parts are ordinarily subjected to a rounding finish independent of a press working process, or a coating works to cover the entire corner parts with vinyl chloride or polyethylene or the like. As a result, there has been encountered a problem in terms of cost-up owing to such a finishing work or a coating work.
Additionally stated, as illustrated in FIG. 39, since a seat belt anchorage plate is formed with a plate shaped base 2, the area of one long edge part 691-8 for holding the belt 13 is small, so that surface pressure exerting on the belt 13 is disadvantageously increased.
The present invention was made by taking these problems into account and an object of the present invention is to provide a seat belt anchorage plate for a seat belt device and a method for manufacturing it capable of completely reducing surface pressure to be exerted on the belt even when tension acts on the belt.